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Effect of Prolonged Heat Treatments on Mechanical Properties of Inconel 625 Processed by Laser Powder Bed Fusion
No full textLaser powder bed fusion (LPBF) process is an Additive Manufacturing (AM) technology that allows the production of complex shaped components in an easier way than traditional ones. The as-fabricated Inconel 625 (IN625) parts by LPBF require post heat treatments to meet the industrial requirements in order to reduce the residual stresses and obtain tailored microstructure. However, it is also fundamental to control the microstructural evolution of the IN625 components owing to the thermal exposure over 500 °C during service, which can have a significant impact on their mechanical properties. This study aims to investigate the influence of prolonged heat treatments on microstructure and mechanical properties of IN625. The prolonged heat-treated IN625 samples are investigated by Optical Microscope (OM), Field Emission Scanning Electron Microscope (FESEM) and X-Ray Diffraction (XRD) analysis, whereas the mechanical properties are evaluated by hardness test
The Polyvalent heat pumps technology in retrofit of existing HVAC systems
Get PDFIn terms of existing buildings' retrofit, historical and non-residential buildings clearly represent two challenging categories. In historical buildings, due to architectural constraints, acting on the technical side is often the only way to reduce consumptions, while non-residential buildings usually require simultaneous production of hot and chilled water. In these cases, Polyvalent heat pumps represent an interesting solution, able to guarantee significant reductions of primary energy consumptions. In detail, a Reference Building for an historical office was simulated in three Mediterranean cities, using EnergyPlus software and some evaluation tools specifically set to emulate the energy performances of the examined HVAC technologies
Critical raw materials and the circular economy
No full textThis report is a background document used by several European Commission services to prepare the EC report on critical raw materials and the circular economy, a commitment of the European Commission made in its Communication ‘EU action plan for the Circular Economy'. It represents a JRC contribution to the Raw Material Initiative and to the EU Circular Economy Action Plan. It combines the results of several research programmes and activities of the JRC on critical raw materials in a context of circular economy, for which a large team has contributed in terms of data and knowledge developments. Circular use of critical raw materials in the EU is analysed, also taking a sectorial perspective. The following sectors are analysed in more detail: extractive waste, landfills, electric and electronic equipment, batteries, automotive, renewable energy, defence and chemicals and fertilisers. Conclusions and opportunities for further work are also presented
SEISMIC RELIABILITY-BASED DESIGN OF INELASTIC STRUCTURES WITH DIFFERENT VALUES OF THE POSTYIELDING STIFFNESS ISOLATED BY FPS
No full textThis work aims to evaluate the seismic reliability of nonlinear systems, considering both a hardening and softening post-yielding behavior, isolated by friction pendulum devices (FPS) for different values of the strength reduction factor. The isolated structure is described through an equivalent 2dof model, whereas, the FPS behavior is described by a velocity de-pendent model. An extensive parametric study is carried out encompassing a wide range of inelastic building properties considering different values of the post-yielding stiffness, differ-ent seismic intensity levels and considering the friction coefficient as a random variable. De-fined a set of natural seismic records and scaled to the seismic intensity corresponding to life safety limit state for L'Aquila site (Italy) according to NTC08, the yielding characteristics of the superstructures are consequently designed according to NTC08 for different values of the strength reduction factor. Incremental dynamic analyses (IDA) are developed to evaluate the seismic fragility curves of both the inelastic superstructure and the isolation level assuming different values of the corresponding limit states. Integrating the fragility curves with the seismic hazard curves related to L'Aquila site (Italy), the reliability curves of the inelastic base-isolated structural systems, with a design life of 50 years, are derived and proposed in order to provide useful design recommendations depending on both the strength reduction factors and post-yielding behavior
Novel Amphipathic Polyurethane based Colloidal Dispersions to Combat Gram-positive bacteria
No full textEnergy harvesting from aeroelastic vibrations induced by discrete gust loads
No full textThis article evaluates the amount of energy that can be extracted from a gust using an aeroelastic energy harvester composed of a flexible wing with attached piezoelectric elements. The harvester operates in a subcritical flow region. It is modeled as a linear Euler-Bernoulli beam sandwiched between two piezoceramics. The extended Hamilton's principle is used to derive the harvester's equations of motion and an eigenfunction expansion is used to form a three-degree-offreedom reduced-order model. The degrees of freedom retained in the model are two flexural degrees for the in-plane and out-of-plane displacements, and a torsional degree for the rotational displacement. Wagner and Ku¨ssner functions are used to represent the unsteady aerodynamic and gust loading, respectively. The amount of energy extracted from the system is then compared for two different deterministic gust profiles, 1-COSINE and two sharp-edged gusts forming a square gust, for various magnitudes and durations. The results show that the harvester is able to extract more energy from the square gust profile, although for both profiles the harvester extracts more power after the gust has subside
IoT for Ambient Assisted Living: Care4Me - A Healthcare Support System
No full textResearch activities on healthcare support systems mainly focus on people in their own homes or nurses and doctors in hospitals. A limited amount of research aims at supporting caregivers that work with people with disabilities in assisted living facilities (ALFs). This chapter explores and applies the Internet of Things to the ALF context. In particular, it presents the design, the implementation, and the experimental evaluation of Care4Me, a system supporting the daily activities of assistants. The requirements for designing and implementing Care4Me derive from a literature analysis and from a user study. The solution combines wearable and mobile technologies. With this healthcare support system, caregivers can be automatically alerted of potentially hazardous situations. Furthermore, inhabitants can require assistance instantly and from any point of the facility. The system was evaluated in two ways. The authors performed a functional test with a group of professional caregivers, and deployed the system in an ALF in Italy, collecting the opinions of caregivers and inhabitants
On the contingent value of IT-based capabilities for the competitive advantage of SMEs: Mechanisms and empirical evidence
No full textThis article assesses the value of the capabilities developed through the use of Information Technology (IT) in Small and Medium Enterprises (SMEs), by analysing whether these capabilities are a determinant of the intra-industry differential in their performance. Our work makes two principal contributions to the understanding of the value of IT. First, the article shows that externally oriented IT-based capabilities have a greater impact on the firm's intra-industry differential in revenue growth and profitability than those capabilities focused on efficiency improvement, namely internally oriented IT-based capabilities. Essentially, this result is consistent with two facts: i) the greater importance that market and supply chain relationships have for firms with a limited scale compared to efficiency improvement, and ii) the greater social and organizational complexity captured by IT use in firm's external relationships. Second, through a contingent perspective, our article shows that the returns of externally oriented IT-based capabilities are more likely to provide performance advantages to SMEs in contexts of low munificence and low dynamism. This evidence thus highlights that under these environmental conditions, IT is more likely to hinder than to facilitate SMEs' ability to respond to market changes and new opportunities
Pipe Jacking in Sandy Soil Under a River in Shenyang, China
No full textThis paper provides an overview of a pipe jacking project of the Wu'ai Electric Power Tunnel, funded by Shenyang Power Company and constructed under the supervision of China Railway Construction Corporation in Shenyang, China. This project involves excavation of three jacking shafts and drilling tunnels by pipe jacking technique. A 3.5 m diameter reinforced concrete pipe was jacked below the Hunhe River over a length of 1000 m. Hand shield approach was adopted on the river bank as an alternative of operating an earth pressure balance micro tunnel boring machine under the river. The stress-strain behavior of shafts under the maximum applied jacking forces was evaluated by means of finite element analyses. Monitoring data (i.e., tunnel alignment, jacking forces, resistance at the jacking head, frictional resistance and torque of the boring machine) were collected during the jacking process and are presented here. A tunnel face collapse was experienced; the corresponding countermeasure actions adopted are described. The jacking design (i.e., pipe, jacking machine, and shafts) and remediation for tunnel failure may provide reference for future projects and assist in the development of new design guidelines